Endoscope insertion portion

1. An endoscope insertion portion having an insertion axis in a longitudinal direction thereof, comprising: a distal end portion; a first image pickup portion disposed in the distal end portion, having a first longitudinal axis parallel to the insertion axis, and comprising a first observation optical system for condensing first photographing light and a first image pickup device, a first optical axis parallel to the insertion axis being set to the first observation optical system; and a second image pickup portion disposed in the distal end portion, having a second longitudinal axis parallel to the insertion axis and to the first longitudinal axis of the first image pickup portion to provide an axis of vision parallel to the first image pickup portion, and comprising a second observation optical system for condensing second photographing light and a second image pickup device, a second optical axis parallel to the insertion axis and to the first optical axis being set to the second observation optical system, wherein the first and second image pickup portions are configured such that the first image pickup device connected to a proximal-most end portion of the first observation optical system and the second image pickup device connected to a proximal-most end portion of the second observation optical system are located at different positions from each other in a direction of the insertion axis, by setting a length from a distal-most end to a proximal-most end of the first observation optical system to be greater in the direction of the insertion axis than a length from a distal-most end to a proximal-most end of the second observation optical system to avoid the first and second image pickup devices from being close to each other.

2. The endoscope insertion portion according to claim 1 , comprising: a first signal cable for transmitting a first image signal based on electric charges obtained by the first image pickup device; a first cable contact portion for electrically connecting the first image pickup portion and the first cable; a second signal cable for transmitting a second image signal based on electric charges obtained by the second image pickup device; and a second cable contact portion for electrically connecting the second image pickup portion and the second cable, wherein the first and second image pickup portions are each located in the distal end portion to be apart from each other by a predetermined distance in the insertion axis direction to avoid the first and second cable contact portions from being close to each other.

3. The endoscope insertion portion according to claim 1 , wherein: the first image pickup portion is disposed at generally center of the distal end portion, and has a proximal end part coated by a rigid first insulating tube, the second image pickup portion disposed on an outer circumferential side of the distal end portion, and has a proximal end part coated by a rigid second insulating tube, and the first insulating tube is located on a more proximal end side along an insertion axis direction than the second insulating tube.

4. The endoscope insertion portion according to claim 1 , wherein the first image pickup portion is for obtaining a normal light observation image and the second image pickup portion is for obtaining a special light observation image.

5. The endoscope insertion portion according to claim 4 , wherein the special light observation image is a fluorescent light observation image.

6. The endoscope insertion portion according to claim 4 , wherein the first and second observation optical systems are magnification optical systems, one of which has a magnification higher than that of the other.

7. The endoscope insertion portion according to claim 1 , wherein the first and second observation optical systems are magnification optical systems, one of which has a magnification higher than that of the other.

8. The endoscope insertion portion according to claim 1 , wherein the first image pickup device and the second image pickup device are disposed in the distal end portion such that an agreement is made between the first and second electric charge transfer directions in which electric charges are transferred from each photoelectric conversion device of the respective image pickup devices.

9. The endoscope insertion portion according to claim 8 , further comprising a bending portion bendable in a direction generally agreeing with an up/down direction of a monitor screen on which an endoscope image is displayed, wherein the first electric charge transfer direction, in which electric charges are transferred from each photoelectric conversion device, agrees with the generally agreeing direction in which the bending portion bends.

10. The endoscope insertion portion according to claim 8 , further comprising: a first fixing member for fixing the distal end portion and the first image pickup device; and a second fixing member for fixing the second image pickup device to the distal end portion such that a horizontal transfer direction of the first image pickup device and a horizontal transfer direction the second image pickup device generally agree with each other.

11. The endoscope insertion portion according to claim 10 , further comprising a bending portion bendable in a direction generally agreeing with an up/down direction of a monitor screen on which an endoscope image is displayed, wherein the horizontal transfer directions generally agree with a direction generally orthogonal to the generally agreeing direction in which the bending portion bends.

12. The endoscope insertion portion according to claim 11 , comprising: a first converting portion for converting a signal from the first image pickup device into a first image signal to be displayed on the monitor as a first endoscope image; and a second converting portion for converting a signal from the second image pickup device such that the bending direction of the bending portion generally agrees with an up direction of the first endoscope image displayed on the monitor, and outputting an image signal for displaying a second endoscope image on the monitor.

13. The endoscope insertion portion according to claim 1 , further comprising a bending portion bendable in at least two directions, wherein an image signal from the first image pickup device is transmitted to a monitor for displaying a first endoscope image, the bending portion is operable to be bent in an up direction of the first endoscope image displayed on the monitor, and the second image pickup device is disposed in the distal end portion such that an up direction of a second endoscope image displayed on the monitor by an image signal outputted by the second image pickup device generally agrees with the up direction of the first endoscope image.

14. The endoscope insertion portion according to claim 13 , comprising: a first converting portion for converting a signal from the first image pickup device into a first image signal to be displayed on the monitor as the first endoscope image; and a second converting portion for converting a signal from the second image pickup device such that the bending direction of the bending portion generally agrees with an up direction of the first endoscope image displayed on the monitor, and outputting an image signal for displaying the second endoscope image on the monitor.